Bolt operating mechanism for machine guns



J. L. HATCHER Filed April 22. 1931 I llwlzlwllm. Llamas 1-7.. at: E1"

ATTORNEY May 17, 1932.

sour OPERATING MECHANISM FOR MACHINE GUNS Patented May 17, 1932 hdSdAtdFATE @FFEQE JAMES L. HATOHER, on THE UNITED slnrns ARMY, wrnonns'rnn,vrne n n Application filed April 22, 1931.

Serial No. 531,972.

(GRANTED UNDER THE ACT OF MABGE 3, 1883, AS AMENDED APRIL 30, 1928; 370O. 757) The invention described herein may he manufactured and used byor for the Government for governmental purposes, without the payment tome of any royalt there- This invention relates to a bolt operatingmechanism for machine guns.

Machine guns are provided with a bolt handle to permit manual retractionof the bolt in order to reproduce the action of the gun mechanism duringfiring for the purpose of initially loading the gun and correctingstoppages. Then agun is mounted, as in aircraft, so that the bolt handleis inaccessible to the gunner, an auxiliary operating mechanism isprovided.

The operating mechanism of the present invention is of the rigid slidebar type having a pivoted handle arranged to act as a lever in raisingthe bar from its latch-plate and in initially retracting the bar whenthe gun barrel is locked to the bolt. The bar is also provided with afixed handle to replace the handle normally provided on the bolt stud ofthe gun.

lVith the foregoing and other objects in view, the invention resides inthe novel arrangement and combination of parts and in the details ofconstruction hereinafter (lee scribed and claimed, it being understoodthat changes in the precise embodiment of the invention herein disclosedmay be made within the scope of what is claimed without departing fromthe spirit of the invention.

A practical embodiment of the invention is illustrated in theaccompanying drawings, wherein:

Fig. l is a view in side elevation of a machine gun equipped with theimproved bolt operating mechanism.

Fig. 2 is a plan view of Fig. 1.

Fig. 3 is a. sectional View on the lines 38 of Fig. 2.

Referring to the drawings by numerals of reference There is shown theside plate 6 of a machine gun having a longitudinally extending slot 7in which the stud S of the breech bolt reciprocates during actuation ofthe gun. Secured to the side plate at either end of the slot are frontand rear brackets 9 and 1Q for supporting and guiding a slide bar 11parallel to and directly below the slot '2',

A collar 12 (Fig. 3) secured to the bar 11 by means of a threaded pin 13is formed with an upstanding finger 14 engageable with the forward faceof the stud 8 so that rearward movement of the bar will retract the stud8 and the bolt of the gun while forward movement of the stud will returnthe slide bar, A, handle 15 fastened to the pin 13 by means of a pin 16replaces the handle that is usually provided on the stud 8.

The slide bar 11 extending a short distallfle beyond the rear bracket 10and fitting into the bifurcated upper portion of a handle 1? is securedintermediately of the ends of the handle by apivot pin 18. A roller 19also fitted in the bifurcated portion and secured by a pivot pin 20 atone end of the handle above the pivot pin 18 normally engages a curvedcam surface 21 on the rear bracket 10. This surface constitutes asupport for the roller and serves as a fulcrum for the handle when thelatter is acting as a lever.

The pivotally mounted handle is maintained in a predetermined positionby means of a stop pin 22 and aspring-pressed plunger 23. The pin 22 isfixed in the handle and engag h pper surface of the slide bar while theplunger 23 bears against the under? cut rear face 2% of the slide barand works in a downwardly inclined recess 25 in the handle. The plungernormally tending to rotate the handle downwardly is opposed by thestop-pin 22. Upward rotation of the handle is limited by contact of theface 241 of the bar with the handle.

The under side of the slide bar is provided with spaced recesses ornotches 26 and 27, the rear recess 26 being engaged with the latch-plate28 of the rear bracket 10 when the slide bar is fully forward as shownin Fig. 1, and the front recess 27 being engage able therewith when theslide bar is retracted for the purpose of holding the stud 8 and itsbreech bolt in the retracted position. Spaced fiat springs 29729 carriedon the upper side of the slide bar each overlie one of the re.- GBSSBSand are adapted to engage the rear bracket to depress the slide bar andinsure engagement of the recesses with the latchplate.

A collar on the slide bar adjacent its rear end is arranged to engagethe lower portion of the rear face of the bracket 10 to positively limitforward movement of the slide bar.

In the normal automatic operation of the gun the slide bar remains inthe forward position and the bolt stud 8 reciprocates freely in rear ofthe finger lt. When it is desired to manually retract the bolt by meansof the handle 17, the handle is grasped and pulled rearwardly. Since theslide bar is locked against rearward displacement by virtue of theengagement of the recess 26 and latch plate 28, the effect of therearward pull on the handle will be to rotate it about its pivot 18 andcause the roller 19 to ride up the cam surface 21 thereby bodily raisingthe handle and the slide bar which is attached to it until the bar isarrested by engaging the rear bracket. At this point the rollersupported by the rear bracket comes into play as the fulcrum of a leverand the continued rearward pull on the handle serves to smoothlyinitiate retraction of the slide bar and the bolt of the gun which atthis time is being unlocked from the barrel. From then on the handlefunctions merely as an attachment on the slide bar whereby completeretraction is efiected.

At the end of the rearward stroke of the slide bar the front spring 29will act on the rear bracket to depress the bar and .efiect engagementof the recess 27 andvlatch plate 28 unless an upward pressure isexerted. Consequently the tendency of the slide bar to be automaticallyheld in the retracted position may be overcome at the will of theoperator.

The handle 15 provided intermediate the length of the slide bar is moreconveniently employed when the operator is, not in a favorable positionto pull back on the handle 17.

I claim:

1. The combination with a machine gun having a reciprocating bolt andbolt stud, of a front and rear bracket secured to the side of the gun, aslide bar reciprocally mounted in the brackets, a finger on the slidebar en gageable with the forward face of the bolt stud, and under sideof the slide bar provided with spaced recesses for engagement with therear bracket, springs on the upper side of the slide bar overlying therecesses and engageable with the rear bracket to depress the slide abar, and a pivoted handle on the slide bar adapted to fulcrum on thesupport.

2. Mechanism for manually operating the bolt of a machine gun includingsupporting means securable to the gun, a slide carried by the supportingmeans and engageable with the bolt stud, a handle pivoted intermediateits ends to the slide and having limited movement relative thereto, aspringpressed plunger mounted in the handle and acting on the slide tonormally rotate the handle to one limit ofits movement, a'roller on oneend of the handle, a cam surface on the supporting means against whichthe roller normally bears when the slide is fully forward.

3. Mechanism for manually operating the bolt of a machine gun includingsupporting means securable to the gun, a slide carried by the supportingmeans and engageable with the bolt stud, a handle pivoted intermediatement relative thereto, means for maintaining the handle in apredetermined position with respect to the slide bar, a roller on oneend of the handle, a cam surface on the supporting means against whichthe roller normally bears when the slide is fullyforward. a. Mechanismfor manually operatingthe bolt of a machine gun includingsupportingmeans securable to the gun, a slide recip-' rocally mounted inthe supporting means, and engageable with the bolt, means for latchingthe slide against reciprocation, a handle pivi oted on therear end ofthe slide, and an inclinded fulcrum against which one end of the handlenormally bears when the slide is fully forward. 2

5. Mechanism for manually operating the bolt of a machine gun includingsupporting means securableto the gun, a slide reciprocally mounted inthe supporting means, and engageable with the'bolt, means for latchingtheslide against reciprocation, and means on the slide cooperating withthe supporting means for unlatching the slide and initiating retractionof the slide. a

6. Mechanism for manually operating the bolt of a machine gun includingsupporting means securable to the gun, a slide reciprocally mounted inthe supporting means, and engageablc with the bolt, means for latchingthe slide against reciprocation,and means on the slide cooperating withthe supporting means for unlatching the slide.

7. Mechanism for manually operating the bolt of a machine gun includingsupportin means securable to the gun, a slide carrie by the supportingmeans and engagcable. with the bolt, and means on the slide fulcrumed onthe supporting means in initially retracting the slide.

JAMES L. HATCHER.

80 its ends to the slide and having limited move- 7

